When we think of cryptozoology, we usually think of Bigfoot, the Yeti, and the Loch Ness Monster, creatures that are - let's face it - probably legendary. But some cryptids are real: just ask the platypus, okapi, and giant squid.

Of course, all of those are former cryptids - they've long since been "officially" discovered. But the fact is that all these creatures were not so long ago considered the stuff of myths and hoaxes by serious zoologists, and that something like the platypus was considered just as unlikely as Sasquatch. These are all real creatures that, at least for a moment, blurred the line between zoology and cryptozoology.

This summer, io9 is going cryptozoological. We're offering a $2000 bounty to the person who sends us the best authentic photo or video of a "cryptid," or mystery animal. And that's just the beginning of Cryptid Summer. More »